21184252105 has 4 divisors (see below), whose sum is σ = 25421102532. Its totient is φ = 16947401680.

The previous prime is 21184252087. The next prime is 21184252129. The reversal of 21184252105 is 50125248112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3274586176 + 17909665929 = 57224^2 + 133827^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21184252105 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2118425206 + ... + 2118425215.

It is an arithmetic number, because the mean of its divisors is an integer number (6355275633).

Almost surely, 2^21184252105 is an apocalyptic number.

It is an amenable number.

21184252105 is a deficient number, since it is larger than the sum of its proper divisors (4236850427).

21184252105 is an equidigital number, since it uses as much as digits as its factorization.

21184252105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4236850426.

The product of its (nonzero) digits is 6400, while the sum is 31.

The spelling of 21184252105 in words is "twenty-one billion, one hundred eighty-four million, two hundred fifty-two thousand, one hundred five".